Trowel for pipe lining material



June 15, 1965 .w. E. PERKINS TROWEL FOR PIPE LINING- MATERIAL 2 Sheets-Sheet 1 Filed Feb. 3, 1964 INVENTOR. W4 RAEN E. PER/0N5 BY W6MM ATTORNEYS June 15, 1965 w. E. PERKINS TROWEL FOR PIPE LINING MATERIAL 2 Sheets-Sheet 2 INVENTOR. WA RREN E. PER/(1N5 BY @M ATTORNEYS Filed Feb. 3, 1964 3,188,710 TROWEL FOR PIPE LINING MATERIAL Warren E. Perkins, Grand Island, N.Y., assignor to Perkins Pipe Linings Inc., Grand Island, NY. Filed Feb. 3, 1964, Ser. No. 342,031 4 Claims. (Cl. 25-38) This'invention relates to pipe lining apparatus wherein a protective coating of mortar or similar material in plastic condition is applied to the interior of a pipe and more particularly to a troweling means for smoothing the surface of such an interior coating directly after the same has been applied to or deposited against the interior wall of a pipe.

My prior Letters Patent No. 2,924,867, dated February 16, 1960 and No. 2,987,794, dated June 13, 1961, show troweling apparatus for this general purpose wherein the trowel device is adapted to be drawn through underground pipe and the former patent in particular shows apparatus for depositing a continuous layer of mortar against the interior of the pipe and for smoothing the same by directly following the depositing apparatus with a troweling device. The present invention provides a new and improved troweling means for use in a similar manner.

The prior art contains a number of examples of sheet metal frusto-conical trowels for the general purpose of smoothing an interior mortar coating by pulling the trowel through a pipe wherein such mortar has been applied to the interior surface of the pipe. The trowel is drawn through the pipe with its small end first and the large or trailing end of the trowel which performs the mortarsmoothing function is necessarily resilient and must be readily expansible and contractible in a diametral direction while still generally retaining its circular form or tending to maintain such form even though local conditions may cause the large troweling end of the trowel to assume somewhat elliptical or other distorted forms temporarily.

Since trowels of this type are drawn through a pipe under conditions where the operation of the trowel cannot be observed during its functional periods, the necessity for safe, accurate and foolproof operation and selfadjustment for various physical conditions which are encountered by the trowel in its passage through a pipe is of greatimportance.

The trowel of the present invention meets the unusual and demanding requirements of a satisfactory trowel for acting at the interior surfaces of pipes in a simple, effective and economical manner. In the trowel of the present invention a plurality of trowel plate segments are curved and formed in such manner that they combine to form a resiliently expansible frusto-conical trowel body.

As will appear later herein, the trowel plates of the trowel of the present invention are pivoted flatwise against each other at the small or leading end of the frusto-conical trowel body so that the leading end of the trowel is of a relatively fixed diameter and the large or troweling end is rendered automatically adjustable to varying diameters through relative pivotal movement of the trowel plates against each other at the small or leading end of the trowel to produce varying diameters at the large end of the trowel and correspondingly varying vertex angles of the frusto-conical trowel body.

Separate means are provided at the interior of the large or trailing end of the trowel body for resiliently urging overlapping portions of the trowel plates against each other despite relative intersliding movement of the plates at the large end of the trowel occasioned by diametral adjustment. Since the curvature of the flexible trowel plates at the large end of the trowel varies during troweling, the resilient means just referred to, which acts across United States Patent "ice overlapping plate portions in a diametral direction, re tains the overlapping plate portions relatively closely against each other during such adjustments in curvature and relative inter-sliding of the trowel plates while still maintaining circumferential continuity of the large end of the trowel.

In addition to this radially acting resilient means, the trowel of the present invention includes extension coil spring members located within the trowel body adjacent to its large end and acting across the overlapping plate portions in such manner that a pulling or extension spring force is caused to exert a resilient spreading force on the trowel plates at the overlapping portions thereof to yieldably urge the large end of the trowel body in a diameterincreasing direction. This means exerts resilient radially. outward trowelling pressure and allows for contraction and expansion of the large end of the trowel as conditions require.

The use of extension springs for this purpose instead of the usual compression springs is novel and important since the extension spring requires no guiding or retaining surfaces, the spring being suspended in space excepting where it ends connect with anchoring means carried by the trowel plates. Furthermore, the extension coil springs of the present invention are less subject to fouling due to their lack of lateral restraint or interference and also due to the fact that mortar which may enter between the coils of the spring will not prevent free extension of the spring. A further important feature of the extension coil spring trowel expansion arrangement of the present invention resides in the fact that expansion of the trowel under a fairly constant spring force is afforded through a relatively wide diametral range, as compared with prior art proposals of this general type.

A primary problem and consideration in the construction of a trowel of this general nature is to avoid conditions which permit mortar to enter between parts or in recesses of one kind or another, which mortar hardens and fouls the parts and prevents free relative resilient.

adjusting movements of the parts. The general manner in which the trowel plates of the present device are relatively supported, oriented and interconnected provides a structure which minimizes the possibility of the parts thus becoming fouled with mortar. The resilient means provided herein for preventing separation of the overlapped portions of the trowel plates, particularly at their trailing portions, without substantially modifying or affecting the basic resilient radial expansible relationship of the trailing portions of the plates, further contributes in an important manner to the general non-fouling structure of the trowel.

This is particularly important because of the blind or remote control conditions under which trowels of this nature are most often used. In ordinary use of a troweling device of this type obstructions within a pipe frequently bear locally against the troweling surfaces and if such as obstruction bears against the surface of a trowel plate adjacent to the area where such trowel plate underlaps the other plate, then the plates tend to separate in a radial direction and if such separation is permitted mortar inevitably enters the space created by such separation to a greater or less degree and prevents the parts from returning to proper overlapping condition even after the trowel has moved past the obstruction.

The arrangement of the present invention is such that separation of the plates as described above is effectively prevented and the overlapping parts of the trowel plates are held in intimate inter-sliding abutment even while such local distorting forces are applied thereto so that' The accomplish the trowel body is a veryimpertant improvement in devices of this type. Expansion and contraption thus take place without interrupting the continuous closed loop configuration of the trowel as viewed from its large' end.

A single specific embodiment of the principles of the present invention is illustrated in the accompanying drawing and described in detail in the. following specification.

However, it is to be understood that such embodiment is byway of example only and that various mechanical modifications may be introduced without departing'from the spirit of the. invention, the scope of which is limited only as defined in the appendedclaims.

of FIG. 2'viewed from the small or leading end thereof;

FIG. 5 is a fragmentarycross-sectional.view on the line V'V of FIG. 3 ;and

FIG. 6 is a fragmentary cross-sectional view on the line VI- VI of FIG. 4.'

Like charactersof reference. denote like parts throughout the several figures of the drawing and, referring particularly to FIG. l, the numeral 10 designates generally a frusto-conical 'sheetrnetal trowelbody having-three rods 11 connected to the small end thereof and leading to a swivel member 12 which rnay be connected to any suitable tractionmeans but is .usually connected to a mortar applying machine in the mannerillustrated in the above-enumerated prior patents whereby the trowel is with respect to the trowel body, extending through a slot 24 in the underlying overlapped portion of the adjacent trowel plate 13, whereby the overlapping portions of the trowel plates may slideagainst each other in a circumferential direction.

A compression coil spring 25 is disposed about a bushing 26 onscrew'22 and a pair of spring seat collars27 and 28, likewise disposed about bushing 2 6, permit the coil spring to react between a nut 30 on screw 22 and, through the mediumof washers 31, against the interior surface of.

the underlying trowel plate portion, thus urging the same against the overlying portionof the adjacent trowel plate tov which screw 22 is welded;

A bracket is welded to the interior surface of the underlying trowel plate portion and is slottedlikewise as at 24 whereby screw 22 passes therethrough. Bracket 35 includes an upstanding end flange 36 to which one end of an extension coil spring 37 is attached, as clearly shown in FIG. 3. The opposite endof spring 37 is'attached indirectly to the outer overlapping'trowel plate portion, in

the' present instance, by connect-ion'with one of the washers 31 of screw 22 as by welding or'the like. V Referring to'FIGf3' and particularly to the lower screw 7 1 2.2 and sp1*ir1g 37 thereof, it will be noted that the. pull of the extensionspring 31-,acting-against flange-36, tends to slide the underlying trowel plateportion 36 in aclock- V wise directionfand ,tends jto slide the outer or overlying trowelplate: portion, through the'me diur'n of screw. 22 in drawn through the interior of .a pipe immediatelyffollowing the application of mortar to such interior.

' The trowel body 10 may be made up offvarious numbers of individual trowel .plates and in. FIGS 2, 3 and 4 the numeral 13 designates threeindividual trowel plates which overlap along longitudinal portions. thereof to form the frusto-conical trowel body 10.

In FIG. 2 the numeral 15'designates' the overlapping V edge of one of the. trowel plates 13 and the numeral 16 designates the underlappingedge of an adjacent trowel plate 13. The overlapped portions. ofadjacent trowel plates 13 are pivoted toeach other adjacent to the small or leading "end of the trowel body 10 by connections which'may, comprise headed studs 17. and washers 18 which are retained by peening or riveting'the .outer'end of the shank of "each stud 17. It will be noted thatthe shank portion of each stud extends through the over lapped layers of trowel plates. 13 and pivots the adja cent plates toeach other for relative intersliding move nie nt." Thus the several trowel plates are free tornove I V I claim:

a counterclockwise direction. This tends to slide the plates in a diameter-increasing direction- This expansion movement will normally be'limitcd by engagement of screws '22 in the ends o f,slots 24. and when the trowel is in use in a pipe, the diameter will. normally be determined,

'yieldably, bythe constriction imposed by the mortar against which the trowel isacting.

1. Trowel means for'srnoothing a layer of plastic lining material in an'interior generally cylindrical surface, said trowel means comprising a plurality of longitudinally extending overlapping plate members which combine to form a generally frusto-eonioal trowel body, said plate members having mounting means at the small end of the.

trowel body constraining said plate members to a relatively fixed diameter at such smallend but permitting inward and outward movement of the plate members at the large end of the trowel body whereby the large end may expand and contract, means at the overlapping portions of said plate members adjacent to the large end of said body for resiliently retaining said'overlapping portions against separation while permitting relative interslidingmove ment thereof to permit circumferential expansion and contractionfof said large end, and expansion means. at

'the large end of said trowel body at overlapping portions of adjacent plate member, said expansion means comprisoutwardly or; inwardly at the large end'of the trowel to increase or decrease the vertex angle of the frusto-con'ical.

trowel body'10'.

Each trowel plate 1 3 is'perforated adjacent to its small or leading end as at 20, the perforation 20 o f eachlplate 1 3 being located approximately midway between the two pivotal connections 17., 18 of each plate 13, Screw and nut connections through the'adjacent ends of the. rods 11 and the perforations 2t) connect the rods to the trowel body. In this way the tractive ,force. is applied to the trowel body without tending to produce distortive eflfects;

p n t e S m The. manner in which the overlapping portions of the" trowel. plates 13 are associated at the large, endof the trowel body 10 to prevent separation of such overlapping portions while permitting expansive and .contractive movements, thereof'will now be. described. .A screw 22 has its head portion 23. welded to the interior surface I of the outer overlapping portion of each trowelplate13.

The shank portion of screw 22 projects-radially inwardly the large end of the trowel body whereby the large end may expand and contract, and expansion means at the ing meansjprojecting inwardly fromthe inner. overlapping plate portion, means projecting inwardly from the outer overlapping plate portion, said inner overlapping portion being slotted to permit circumferentialmovement of said 1 last mentioned means relative to said inner overlapping portion,. and a tension spring acting between said two inwardly projecting "means to. urge the edges of said inner and outer overlapping portions circumferentially toward .each'other to' reduce the'overlap and thus expand. the

large. end of the. trowel; body.

2. Trowel means for smoothing a layer of plastic lining.

material in an interior generallycylindrical surface, said trowel means comprising a -p lunality of longitudinally extending overlapping-plate members which combine to form a generally frusto-conical trowel body, said plate memberslhaving mounting means at the small end of the trowel body constraining said plate members to a relatively fixed diameter 'at such small end but permitting inward and outward movement of the plate members at large end of said trowel body at overlapping portions of adjacent plate members, said expansion means comprising means projecting inwardly from the inner overlapping plate portion, means projecting inwardly from the outer overlapping plate portion, said inner overlapping portion beingslotted to permit circumferential movement of said last mentioned means relative to said inner overlapping portion, and a tension spring acting between said two inwardly projecting means to urge the edges of said inner and outer overlapping portions circumferentially toward each other to reduce the overlap and thus expand the large end of the trowel body.

3. Trowel means for smoothing a layer of plastic lining material in an interior generally cylindrical surface, said trowel means comprising a plurality of longitudinally extending overlapping plate members which combine to form a generally frusto-conical trowel body, pivot means connecting overlapping portions of adjacent plate members adjacent to the small end of the trowel body for relative intersliding pivotal movement on an axis generally perpendicular to the frusto-conical surface of the trowel body whereby the large end of the trowel body expands and contracts, means at the overlapping portions of said plate members adjacent to the large end of said body for resiliently retaining said overlapping portions against separation while permitting relative intersliding movement thereof to permit circumferential expansion and contraction of said large end, and expansion means at the large end of said trowel body at overlapping portions of adjacent plate members, said expansion means comprising means projecting inwardly from the inner overlapping plate portion, means projecting inwardly from the outer overlapping plate portion, said inner overlapping portion being slotted to permit circumferential movement of said last mentioned means relative to said inner overlapping portion, and a tension spring acting between said two inwardly projecting means to urge the edges of said inner and outer overlapping portions circumferentially toward each other to reduce the overlap and thus expand the large end of the trowel body.

4. Trowel means for smoothing a layer of plastic lining material in an interior generally cylindrical surface, said trowel means comprising a plurality of longitudinally extending overlapping plate members which combine to form a generally frusto-conical trowel body, pivot means connecting overlapping portions of adjacent plate members adjacent to the small end of the trowel body for relative intersliding pivotal movement on an axis generally perpendicular to the frusto-conical surface of the trowel body whereby the large end of the trowel body expands and contracts, and expansion means at the large end of said trowel body at overlapping portions of adjacent plate members, said expansion means comprising means projecting inwardly from the inner overlapping plate portion, means projecting inwardly from the outer overlapping plate portion, said inner overlapping portion being slotted to permit circumferential movement of said last mentioned means relative to said inner overlapping portion, and a tension spring acting between said two inwardly projecting means to urge the edges of said inner and outer overlapping portions circumferentially toward each other to reduce the overlap and thus expand the large end of the trowel body.

References Cited by the Examiner UNITED STATES PATENTS 258.122 5/82 Richardson et a1.

802,666 10/05 Stieler. 1,019,598 3/12 Clark 25128 2,508,711 5/50 Griffiths l5-104.18 2,924,867 2/60 Perkins 25-38 WILLIAM J. STEPHENSON, Primary Examiner.

MICHAEL V. BRINDISI, Examiner. 

2. TROWEL FOR SMOOTHING A LAYER OF PLASTIC LINING MATERIAL IN AN INTERIOR GENERALLY CYLINDRICAL SURFACE, SAID TROWEL MEANS COMPRISING A PLURALITY OF LONGITUDINALLY EXTENDING OVERLAPPING PLATE MEMBERS WHICH COMBINE TO FORM A GENERALLY FRUSTO-CONICAL TROWEL BODY, SAID PLATE MEMBERS HAVING MOUNTING MEANS AT THE SMALL END OF THE TROWEL BODY CONSTRAINING SAID PLATE MEMBERS TO A RELATIVELY FIXED DIAMETER AT SUCH SMALL END BUT PERMITTING INWARD AND OUTWARD MOVEMENT OF THE PLATE MEMBERS AT THE LARGE END OF THE TROWEL BODY WHEREBY THE LARGE END MAY EXPAND AND CONTRACT, AND EXPANSION MEANS AT THE LARGE END OF SAID TROWEL BODY AT OVERLAPPING PORTIONS OF ADJACENT PLATE MEMEBR, SAID EXPANSION MEANS COMPRISING MEANS PROJECTING INWARDLY FROM THE INNER OVERLAPPING PLATE PORTION, MEANS PROJECTING INWARDLY FROM THE OUTER OVERLAPPING PLATE PORTION, SAID INNER OVERLAPPING PORTION BEING SLOTTED TO PERMIT CIRCUMFERENTIAL MOVEMENT OF SAID LAST MENTIONED MEANS RELATIVE TO SAID INNER OVERLAPPING PORTION, AND A TENSION SPRING ACTING BETWEEN SAID TWO INWARDLY PROJECTING MEANS TO URGE THE EDGES OF SAID INNER AND OUTER OVERLAPPING PORTIONS CIRCUMFERENTIALLY TOWARD EACH OTHER TO REDUCE THE OVERLAP AND THUS EXPAND THE LARGE EDGE OF THE TROWEL BODY. 